The effects of
levodopa are reduced or abolished by pyridoxine, but this interaction does not occur when
levodopa is given with the dopa-decarboxylase inhibitors carbidopa or benserazide, as is usual
clinical practice.
In the rare cases that
levodopa is used alone,
pyridoxine in doses as low as 5 mg daily can reduce the effects of
levodopa and should therefore be avoided. Warn patients about proprietary pyridoxine-containing preparations such as multi- vitamins and supplements. There is no evidence to suggest that a low-pyridoxine diet is desirable.